Brownell received the country's highest award for bravery during combat, the Medal of Honor, for his action aboard the USS Benton during the Battle of Grand Gulf on 2 May 1863 and the Siege of Vicksburg at New Bern on 22 May 1863. He was honored with the award on 16 April 1864.

MOH CITATION:

Served as coxswain on board the U.S.S. Benton during the attack on Great Gulf Bay, 2 May 1863, and Vicksburg, 22 May 1863. Carrying out his duties with coolness and courage, Brownell served gallantly against the enemy as captain of a 9-inch gun in the attacks on Great Gulf and Vicksburg and as a member of the Battery Benton before Vicksburg.